Precursors having a Si—N bond, such as silylamines, have been synthesized through reactions of chlorosilanes with amines or ammonia in the presence of bases (“Disilanylamines. Compounds comprising the structural unit silicon-silicon-nitrogen, as single-source precursors for plasma-enhanced chemical vapor deposition (PE-CVD) of silicon nitride” Schuh, H.; Schlosser, T.; Bissinger, P.; Schmidbaur, H. Zeitschrift fuer Anorganische and Allgemeine Chemie 1993, 619(8), 1347-1352). This type of reaction, however, may not be desirable both in terms of the toxicity and relative instability of chlorosilanes and also because large amounts of ammonium halides may be generated as by-products (“Aminolysis of the Si—Cl bond and ligand exchange reaction between silicon amido derivatives and SiCl4: synthetic applications and kinetic investigations” Passarelli, V.; Carta, G.; Rossetto, G.; Zanella, P. Dalton Trans. 2003, (3), 413-419). Furthermore, since substrates on which the precursors will be deposited need to be compatible with base, a further disadvantage of this traditional approach may also have this limitation to the substrates.
Dehydrogenative coupling reactions of silanes and N-containing molecules may produce chloride-free and base-free Si—N containing compounds. Harrod et al. (“Dehydrocoupling of Ammonia and Silanes”, Liu, H. Q.; Harrod, J. F. Organometallics (1992), 11, p822-827) disclosed that dimethyltitanocene was used as a catalyst for the dehydrocoupling of ammonia with two different phenylsilanes. More recently, Cui et al. (“[(NHC)Yb{N(SiMe3)2}2]-Catalyzed Cross-Dehydrogenative Coupling of Silanes with Amines”, Xie, W.; Hu, H.; Cui, C. Angewandte (2012), 124, p 11303-11306) described dehydrogenative coupling of aromatic silanes and amines catalyzed by an Ytterbium based catalyst. In 2015, dehydrogenative coupling of hydosilanes with amines was described by Mitsudome et al. (“Palladium nanoparticles supported on graphene as catalysts for the dehydrogenative coupling of hydrosilanes and amines”, Garcia et al. Catal. Sci. Tecticnol.2015, 5(3), 1969).
Si—N containing compounds such as (Et2N)2SiHCH2CH2SiH3, (Et2N)2SiHCH2CH2SiH2(NEt2), and (Et2N)2SiHCH2CH2SiH(NEt2)2 were produced by Schmidbaur et al. (“Differences in Reactivity of 1,4-Disilabutane and n-Tetrasilane towards Secondary Amines”, Hubert Schmidbaur and Heinz Schuh, Z. Naturforsch (1990), 45b, 1679-1863) by reacting 1,4-disilabutane H3Si(CH2)2SiH3 and n-tetrasilane H3SiSiH2SiH2SiH3 with the appropriate equivalents of diethylamine in an alkane solvent and in the presence of the two-phase catalyst NaNH2/18-crown-6.
US2015/087139 to Air Products discloses an organoaminosilane compound having the formula (R1R2N)n—SiH3-n—R3—SiH3-m(NR1R2)m.
There exists a need for Si—N dehydrocoupling precursors suitable for chloride-free and base-free vapor depositions to form films with desirable electrical and physical properties.